gdb/memattr.c

   1 /* Memory attributes support, for GDB.
   2
   3    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "command.h"
  23 #include "gdbcmd.h"
  24 #include "memattr.h"
  25 #include "target.h"
  26 #include "value.h"
  27 #include "language.h"
  28 #include "vec.h"
  29 #include "gdb_string.h"
  30
  31 const struct mem_attrib default_mem_attrib =
  32 {
  33   MEM_RW,                       /* mode */
  34   MEM_WIDTH_UNSPECIFIED,
  35   0,                            /* hwbreak */
  36   0,                            /* cache */
  37   0,                            /* verify */
  38   -1 /* Flash blocksize not specified.  */
  39 };
  40
  41 const struct mem_attrib unknown_mem_attrib =
  42 {
  43   MEM_NONE,                     /* mode */
  44   MEM_WIDTH_UNSPECIFIED,
  45   0,                            /* hwbreak */
  46   0,                            /* cache */
  47   0,                            /* verify */
  48   -1 /* Flash blocksize not specified.  */
  49 };
  50
  51
  52 VEC(mem_region_s) *mem_region_list, *target_mem_region_list;
  53 static int mem_number = 0;
  54
  55 /* If this flag is set, the memory region list should be automatically
  56    updated from the target.  If it is clear, the list is user-controlled
  57    and should be left alone.  */
  58 static int mem_use_target = 1;
  59
  60 /* If this flag is set, we have tried to fetch the target memory regions
  61    since the last time it was invalidated.  If that list is still
  62    empty, then the target can't supply memory regions.  */
  63 static int target_mem_regions_valid;
  64
  65 /* If this flag is set, gdb will assume that memory ranges not
  66    specified by the memory map have type MEM_NONE, and will
  67    emit errors on all accesses to that memory.  */
  68 static int inaccessible_by_default = 1;
  69
  70 static void
  71 show_inaccessible_by_default (struct ui_file *file, int from_tty,
  72                               struct cmd_list_element *c,
  73                               const char *value)
  74 {
  75   if (inaccessible_by_default)
  76     fprintf_filtered (file, _("\
  77 Unknown memory addresses will be treated as inaccessible.\n"));
  78   else
  79     fprintf_filtered (file, _("\
  80 Unknown memory addresses will be treated as RAM.\n"));
  81 }
  82
  83
  84 /* Predicate function which returns true if LHS should sort before RHS
  85    in a list of memory regions, useful for VEC_lower_bound.  */
  86
  87 static int
  88 mem_region_lessthan (const struct mem_region *lhs,
  89                      const struct mem_region *rhs)
  90 {
  91   return lhs->lo < rhs->lo;
  92 }
  93
  94 /* A helper function suitable for qsort, used to sort a
  95    VEC(mem_region_s) by starting address.  */
  96
  97 int
  98 mem_region_cmp (const void *untyped_lhs, const void *untyped_rhs)
  99 {
 100   const struct mem_region *lhs = untyped_lhs;
 101   const struct mem_region *rhs = untyped_rhs;
 102
 103   if (lhs->lo < rhs->lo)
 104     return -1;
 105   else if (lhs->lo == rhs->lo)
 106     return 0;
 107   else
 108     return 1;
 109 }
 110
 111 /* Allocate a new memory region, with default settings.  */
 112
 113 void
 114 mem_region_init (struct mem_region *new)
 115 {
 116   memset (new, 0, sizeof (struct mem_region));
 117   new->enabled_p = 1;
 118   new->attrib = default_mem_attrib;
 119 }
 120
 121 /* This function should be called before any command which would
 122    modify the memory region list.  It will handle switching from
 123    a target-provided list to a local list, if necessary.  */
 124
 125 static void
 126 require_user_regions (int from_tty)
 127 {
 128   struct mem_region *m;
 129   int ix, length;
 130
 131   /* If we're already using a user-provided list, nothing to do.  */
 132   if (!mem_use_target)
 133     return;
 134
 135   /* Switch to a user-provided list (possibly a copy of the current
 136      one).  */
 137   mem_use_target = 0;
 138
 139   /* If we don't have a target-provided region list yet, then
 140      no need to warn.  */
 141   if (mem_region_list == NULL)
 142     return;
 143
 144   /* Otherwise, let the user know how to get back.  */
 145   if (from_tty)
 146     warning (_("Switching to manual control of memory regions; use "
 147                "\"mem auto\" to fetch regions from the target again."));
 148
 149   /* And create a new list for the user to modify.  */
 150   length = VEC_length (mem_region_s, target_mem_region_list);
 151   mem_region_list = VEC_alloc (mem_region_s, length);
 152   for (ix = 0; VEC_iterate (mem_region_s, target_mem_region_list, ix, m); ix++)
 153     VEC_quick_push (mem_region_s, mem_region_list, m);
 154 }
 155
 156 /* This function should be called before any command which would
 157    read the memory region list, other than those which call
 158    require_user_regions.  It will handle fetching the
 159    target-provided list, if necessary.  */
 160
 161 static void
 162 require_target_regions (void)
 163 {
 164   if (mem_use_target && !target_mem_regions_valid)
 165     {
 166       target_mem_regions_valid = 1;
 167       target_mem_region_list = target_memory_map ();
 168       mem_region_list = target_mem_region_list;
 169     }
 170 }
 171
 172 static void
 173 create_mem_region (CORE_ADDR lo, CORE_ADDR hi,
 174                    const struct mem_attrib *attrib)
 175 {
 176   struct mem_region new;
 177   int i, ix;
 178
 179   /* lo == hi is a useless empty region */
 180   if (lo >= hi && hi != 0)
 181     {
 182       printf_unfiltered (_("invalid memory region: low >= high\n"));
 183       return;
 184     }
 185
 186   mem_region_init (&new);
 187   new.lo = lo;
 188   new.hi = hi;
 189
 190   ix = VEC_lower_bound (mem_region_s, mem_region_list, &new,
 191                         mem_region_lessthan);
 192
 193   /* Check for an overlapping memory region.  We only need to check
 194      in the vicinity - at most one before and one after the
 195      insertion point.  */
 196   for (i = ix - 1; i < ix + 1; i++)
 197     {
 198       struct mem_region *n;
 199
 200       if (i < 0)
 201         continue;
 202       if (i >= VEC_length (mem_region_s, mem_region_list))
 203         continue;
 204
 205       n = VEC_index (mem_region_s, mem_region_list, i);
 206
 207       if ((lo >= n->lo && (lo < n->hi || n->hi == 0))
 208           || (hi > n->lo && (hi <= n->hi || n->hi == 0))
 209           || (lo <= n->lo && (hi >= n->hi || hi == 0)))
 210         {
 211           printf_unfiltered (_("overlapping memory region\n"));
 212           return;
 213         }
 214     }
 215
 216   new.number = ++mem_number;
 217   new.attrib = *attrib;
 218   VEC_safe_insert (mem_region_s, mem_region_list, ix, &new);
 219 }
 220
 221 /*
 222  * Look up the memory region cooresponding to ADDR.
 223  */
 224 struct mem_region *
 225 lookup_mem_region (CORE_ADDR addr)
 226 {
 227   static struct mem_region region;
 228   struct mem_region *m;
 229   CORE_ADDR lo;
 230   CORE_ADDR hi;
 231   int ix;
 232
 233   require_target_regions ();
 234
 235   /* First we initialize LO and HI so that they describe the entire
 236      memory space.  As we process the memory region chain, they are
 237      redefined to describe the minimal region containing ADDR.  LO
 238      and HI are used in the case where no memory region is defined
 239      that contains ADDR.  If a memory region is disabled, it is
 240      treated as if it does not exist.  The initial values for LO
 241      and HI represent the bottom and top of memory.  */
 242
 243   lo = 0;
 244   hi = 0;
 245
 246   /* Either find memory range containing ADDRESS, or set LO and HI
 247      to the nearest boundaries of an existing memory range.
 248
 249      If we ever want to support a huge list of memory regions, this
 250      check should be replaced with a binary search (probably using
 251      VEC_lower_bound).  */
 252   for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++)
 253     {
 254       if (m->enabled_p == 1)
 255         {
 256           /* If the address is in the memory region, return that memory range.  */
 257           if (addr >= m->lo && (addr < m->hi || m->hi == 0))
 258             return m;
 259
 260           /* This (correctly) won't match if m->hi == 0, representing
 261              the top of the address space, because CORE_ADDR is unsigned;
 262              no value of LO is less than zero.  */
 263           if (addr >= m->hi && lo < m->hi)
 264             lo = m->hi;
 265
 266           /* This will never set HI to zero; if we're here and ADDR
 267              is at or below M, and the region starts at zero, then ADDR
 268              would have been in the region.  */
 269           if (addr <= m->lo && (hi == 0 || hi > m->lo))
 270             hi = m->lo;
 271         }
 272     }
 273
 274   /* Because no region was found, we must cons up one based on what
 275      was learned above.  */
 276   region.lo = lo;
 277   region.hi = hi;
 278
 279   /* When no memory map is defined at all, we always return
 280      'default_mem_attrib', so that we do not make all memory
 281      inaccessible for targets that don't provide a memory map.  */
 282   if (inaccessible_by_default && !VEC_empty (mem_region_s, mem_region_list))
 283     region.attrib = unknown_mem_attrib;
 284   else
 285     region.attrib = default_mem_attrib;
 286
 287   return &region;
 288 }
 289
 290 /* Invalidate any memory regions fetched from the target.  */
 291
 292 void
 293 invalidate_target_mem_regions (void)
 294 {
 295   struct mem_region *m;
 296   int ix;
 297
 298   if (!target_mem_regions_valid)
 299     return;
 300
 301   target_mem_regions_valid = 0;
 302   VEC_free (mem_region_s, target_mem_region_list);
 303   if (mem_use_target)
 304     mem_region_list = NULL;
 305 }
 306
 307 /* Clear memory region list */
 308
 309 static void
 310 mem_clear (void)
 311 {
 312   VEC_free (mem_region_s, mem_region_list);
 313 }
 314 \f
 315
 316 static void
 317 mem_command (char *args, int from_tty)
 318 {
 319   CORE_ADDR lo, hi;
 320   char *tok;
 321   struct mem_attrib attrib;
 322
 323   if (!args)
 324     error_no_arg (_("No mem"));
 325
 326   /* For "mem auto", switch back to using a target provided list.  */
 327   if (strcmp (args, "auto") == 0)
 328     {
 329       if (mem_use_target)
 330         return;
 331
 332       if (mem_region_list != target_mem_region_list)
 333         {
 334           mem_clear ();
 335           mem_region_list = target_mem_region_list;
 336         }
 337
 338       mem_use_target = 1;
 339       return;
 340     }
 341
 342   require_user_regions (from_tty);
 343
 344   tok = strtok (args, " \t");
 345   if (!tok)
 346     error (_("no lo address"));
 347   lo = parse_and_eval_address (tok);
 348
 349   tok = strtok (NULL, " \t");
 350   if (!tok)
 351     error (_("no hi address"));
 352   hi = parse_and_eval_address (tok);
 353
 354   attrib = default_mem_attrib;
 355   while ((tok = strtok (NULL, " \t")) != NULL)
 356     {
 357       if (strcmp (tok, "rw") == 0)
 358         attrib.mode = MEM_RW;
 359       else if (strcmp (tok, "ro") == 0)
 360         attrib.mode = MEM_RO;
 361       else if (strcmp (tok, "wo") == 0)
 362         attrib.mode = MEM_WO;
 363
 364       else if (strcmp (tok, "8") == 0)
 365         attrib.width = MEM_WIDTH_8;
 366       else if (strcmp (tok, "16") == 0)
 367         {
 368           if ((lo % 2 != 0) || (hi % 2 != 0))
 369             error (_("region bounds not 16 bit aligned"));
 370           attrib.width = MEM_WIDTH_16;
 371         }
 372       else if (strcmp (tok, "32") == 0)
 373         {
 374           if ((lo % 4 != 0) || (hi % 4 != 0))
 375             error (_("region bounds not 32 bit aligned"));
 376           attrib.width = MEM_WIDTH_32;
 377         }
 378       else if (strcmp (tok, "64") == 0)
 379         {
 380           if ((lo % 8 != 0) || (hi % 8 != 0))
 381             error (_("region bounds not 64 bit aligned"));
 382           attrib.width = MEM_WIDTH_64;
 383         }
 384
 385 #if 0
 386       else if (strcmp (tok, "hwbreak") == 0)
 387         attrib.hwbreak = 1;
 388       else if (strcmp (tok, "swbreak") == 0)
 389         attrib.hwbreak = 0;
 390 #endif
 391
 392       else if (strcmp (tok, "cache") == 0)
 393         attrib.cache = 1;
 394       else if (strcmp (tok, "nocache") == 0)
 395         attrib.cache = 0;
 396
 397 #if 0
 398       else if (strcmp (tok, "verify") == 0)
 399         attrib.verify = 1;
 400       else if (strcmp (tok, "noverify") == 0)
 401         attrib.verify = 0;
 402 #endif
 403
 404       else
 405         error (_("unknown attribute: %s"), tok);
 406     }
 407
 408   create_mem_region (lo, hi, &attrib);
 409 }
 410 \f
 411
 412 static void
 413 mem_info_command (char *args, int from_tty)
 414 {
 415   struct mem_region *m;
 416   struct mem_attrib *attrib;
 417   int ix;
 418
 419   if (mem_use_target)
 420     printf_filtered (_("Using memory regions provided by the target.\n"));
 421   else
 422     printf_filtered (_("Using user-defined memory regions.\n"));
 423
 424   require_target_regions ();
 425
 426   if (!mem_region_list)
 427     {
 428       printf_unfiltered (_("There are no memory regions defined.\n"));
 429       return;
 430     }
 431
 432   printf_filtered ("Num ");
 433   printf_filtered ("Enb ");
 434   printf_filtered ("Low Addr   ");
 435   if (gdbarch_addr_bit (current_gdbarch) > 32)
 436     printf_filtered ("        ");
 437   printf_filtered ("High Addr  ");
 438   if (gdbarch_addr_bit (current_gdbarch) > 32)
 439     printf_filtered ("        ");
 440   printf_filtered ("Attrs ");
 441   printf_filtered ("\n");
 442
 443   for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++)
 444     {
 445       char *tmp;
 446       printf_filtered ("%-3d %-3c\t",
 447                        m->number,
 448                        m->enabled_p ? 'y' : 'n');
 449       if (gdbarch_addr_bit (current_gdbarch) <= 32)
 450         tmp = hex_string_custom ((unsigned long) m->lo, 8);
 451       else
 452         tmp = hex_string_custom ((unsigned long) m->lo, 16);
 453
 454       printf_filtered ("%s ", tmp);
 455
 456       if (gdbarch_addr_bit (current_gdbarch) <= 32)
 457         {
 458         if (m->hi == 0)
 459           tmp = "0x100000000";
 460         else
 461           tmp = hex_string_custom ((unsigned long) m->hi, 8);
 462         }
 463       else
 464         {
 465         if (m->hi == 0)
 466           tmp = "0x10000000000000000";
 467         else
 468           tmp = hex_string_custom ((unsigned long) m->hi, 16);
 469         }
 470
 471       printf_filtered ("%s ", tmp);
 472
 473       /* Print a token for each attribute.
 474
 475        * FIXME: Should we output a comma after each token?  It may
 476        * make it easier for users to read, but we'd lose the ability
 477        * to cut-and-paste the list of attributes when defining a new
 478        * region.  Perhaps that is not important.
 479        *
 480        * FIXME: If more attributes are added to GDB, the output may
 481        * become cluttered and difficult for users to read.  At that
 482        * time, we may want to consider printing tokens only if they
 483        * are different from the default attribute.  */
 484
 485       attrib = &m->attrib;
 486       switch (attrib->mode)
 487         {
 488         case MEM_RW:
 489           printf_filtered ("rw ");
 490           break;
 491         case MEM_RO:
 492           printf_filtered ("ro ");
 493           break;
 494         case MEM_WO:
 495           printf_filtered ("wo ");
 496           break;
 497         case MEM_FLASH:
 498           printf_filtered ("flash blocksize 0x%x ", attrib->blocksize);
 499           break;
 500         }
 501
 502       switch (attrib->width)
 503         {
 504         case MEM_WIDTH_8:
 505           printf_filtered ("8 ");
 506           break;
 507         case MEM_WIDTH_16:
 508           printf_filtered ("16 ");
 509           break;
 510         case MEM_WIDTH_32:
 511           printf_filtered ("32 ");
 512           break;
 513         case MEM_WIDTH_64:
 514           printf_filtered ("64 ");
 515           break;
 516         case MEM_WIDTH_UNSPECIFIED:
 517           break;
 518         }
 519
 520 #if 0
 521       if (attrib->hwbreak)
 522         printf_filtered ("hwbreak");
 523       else
 524         printf_filtered ("swbreak");
 525 #endif
 526
 527       if (attrib->cache)
 528         printf_filtered ("cache ");
 529       else
 530         printf_filtered ("nocache ");
 531
 532 #if 0
 533       if (attrib->verify)
 534         printf_filtered ("verify ");
 535       else
 536         printf_filtered ("noverify ");
 537 #endif
 538
 539       printf_filtered ("\n");
 540
 541       gdb_flush (gdb_stdout);
 542     }
 543 }
 544 \f
 545
 546 /* Enable the memory region number NUM. */
 547
 548 static void
 549 mem_enable (int num)
 550 {
 551   struct mem_region *m;
 552   int ix;
 553
 554   for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++)
 555     if (m->number == num)
 556       {
 557         m->enabled_p = 1;
 558         return;
 559       }
 560   printf_unfiltered (_("No memory region number %d.\n"), num);
 561 }
 562
 563 static void
 564 mem_enable_command (char *args, int from_tty)
 565 {
 566   char *p = args;
 567   char *p1;
 568   int num;
 569   struct mem_region *m;
 570   int ix;
 571
 572   require_user_regions (from_tty);
 573
 574   dcache_invalidate (target_dcache);
 575
 576   if (p == 0)
 577     {
 578       for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++)
 579         m->enabled_p = 1;
 580     }
 581   else
 582     while (*p)
 583       {
 584         p1 = p;
 585         while (*p1 >= '0' && *p1 <= '9')
 586           p1++;
 587         if (*p1 && *p1 != ' ' && *p1 != '\t')
 588           error (_("Arguments must be memory region numbers."));
 589
 590         num = atoi (p);
 591         mem_enable (num);
 592
 593         p = p1;
 594         while (*p == ' ' || *p == '\t')
 595           p++;
 596       }
 597 }
 598 \f
 599
 600 /* Disable the memory region number NUM. */
 601
 602 static void
 603 mem_disable (int num)
 604 {
 605   struct mem_region *m;
 606   int ix;
 607
 608   for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++)
 609     if (m->number == num)
 610       {
 611         m->enabled_p = 0;
 612         return;
 613       }
 614   printf_unfiltered (_("No memory region number %d.\n"), num);
 615 }
 616
 617 static void
 618 mem_disable_command (char *args, int from_tty)
 619 {
 620   char *p = args;
 621   char *p1;
 622   int num;
 623   struct mem_region *m;
 624   int ix;
 625
 626   require_user_regions (from_tty);
 627
 628   dcache_invalidate (target_dcache);
 629
 630   if (p == 0)
 631     {
 632       for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++)
 633         m->enabled_p = 0;
 634     }
 635   else
 636     while (*p)
 637       {
 638         p1 = p;
 639         while (*p1 >= '0' && *p1 <= '9')
 640           p1++;
 641         if (*p1 && *p1 != ' ' && *p1 != '\t')
 642           error (_("Arguments must be memory region numbers."));
 643
 644         num = atoi (p);
 645         mem_disable (num);
 646
 647         p = p1;
 648         while (*p == ' ' || *p == '\t')
 649           p++;
 650       }
 651 }
 652
 653 /* Delete the memory region number NUM. */
 654
 655 static void
 656 mem_delete (int num)
 657 {
 658   struct mem_region *m1, *m;
 659   int ix;
 660
 661   if (!mem_region_list)
 662     {
 663       printf_unfiltered (_("No memory region number %d.\n"), num);
 664       return;
 665     }
 666
 667   for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++)
 668     if (m->number == num)
 669       break;
 670
 671   if (m == NULL)
 672     {
 673       printf_unfiltered (_("No memory region number %d.\n"), num);
 674       return;
 675     }
 676
 677   VEC_ordered_remove (mem_region_s, mem_region_list, ix);
 678 }
 679
 680 static void
 681 mem_delete_command (char *args, int from_tty)
 682 {
 683   char *p = args;
 684   char *p1;
 685   int num;
 686
 687   require_user_regions (from_tty);
 688
 689   dcache_invalidate (target_dcache);
 690
 691   if (p == 0)
 692     {
 693       if (query ("Delete all memory regions? "))
 694         mem_clear ();
 695       dont_repeat ();
 696       return;
 697     }
 698
 699   while (*p)
 700     {
 701       p1 = p;
 702       while (*p1 >= '0' && *p1 <= '9')
 703         p1++;
 704       if (*p1 && *p1 != ' ' && *p1 != '\t')
 705         error (_("Arguments must be memory region numbers."));
 706
 707       num = atoi (p);
 708       mem_delete (num);
 709
 710       p = p1;
 711       while (*p == ' ' || *p == '\t')
 712         p++;
 713     }
 714
 715   dont_repeat ();
 716 }
 717
 718 static void
 719 dummy_cmd (char *args, int from_tty)
 720 {
 721 }
 722 \f
 723 extern initialize_file_ftype _initialize_mem; /* -Wmissing-prototype */
 724
 725 static struct cmd_list_element *mem_set_cmdlist;
 726 static struct cmd_list_element *mem_show_cmdlist;
 727
 728 void
 729 _initialize_mem (void)
 730 {
 731   add_com ("mem", class_vars, mem_command, _("\
 732 Define attributes for memory region or reset memory region handling to\n\
 733 target-based.\n\
 734 Usage: mem auto\n\
 735        mem <lo addr> <hi addr> [<mode> <width> <cache>], \n\
 736 where <mode>  may be rw (read/write), ro (read-only) or wo (write-only), \n\
 737       <width> may be 8, 16, 32, or 64, and \n\
 738       <cache> may be cache or nocache"));
 739
 740   add_cmd ("mem", class_vars, mem_enable_command, _("\
 741 Enable memory region.\n\
 742 Arguments are the code numbers of the memory regions to enable.\n\
 743 Usage: enable mem <code number>\n\
 744 Do \"info mem\" to see current list of code numbers."), &enablelist);
 745
 746   add_cmd ("mem", class_vars, mem_disable_command, _("\
 747 Disable memory region.\n\
 748 Arguments are the code numbers of the memory regions to disable.\n\
 749 Usage: disable mem <code number>\n\
 750 Do \"info mem\" to see current list of code numbers."), &disablelist);
 751
 752   add_cmd ("mem", class_vars, mem_delete_command, _("\
 753 Delete memory region.\n\
 754 Arguments are the code numbers of the memory regions to delete.\n\
 755 Usage: delete mem <code number>\n\
 756 Do \"info mem\" to see current list of code numbers."), &deletelist);
 757
 758   add_info ("mem", mem_info_command,
 759             _("Memory region attributes"));
 760
 761   add_prefix_cmd ("mem", class_vars, dummy_cmd, _("\
 762 Memory regions settings"),
 763                   &mem_set_cmdlist, "set mem ",
 764                   0/* allow-unknown */, &setlist);
 765   add_prefix_cmd ("mem", class_vars, dummy_cmd, _("\
 766 Memory regions settings"),
 767                   &mem_show_cmdlist, "show mem  ",
 768                   0/* allow-unknown */, &showlist);
 769
 770   add_setshow_boolean_cmd ("inaccessible-by-default", no_class,
 771                                   &inaccessible_by_default, _("\
 772 Set handling of unknown memory regions."), _("\
 773 Show handling of unknown memory regions."), _("\
 774 If on, and some memory map is defined, debugger will emit errors on\n\
 775 accesses to memory not defined in the memory map. If off, accesses to all\n\
 776 memory addresses will be allowed."),
 777                                 NULL,
 778                                 show_inaccessible_by_default,
 779                                 &mem_set_cmdlist,
 780                                 &mem_show_cmdlist);
 781 }